Microstructure and its thermal stability are critical in the development of high-performance Al-Mg alloys.Here,we attempt to tailor Al_(3)(Sc,Zr)precipitates and thus microstructure characteristics to manipulate mecha...Microstructure and its thermal stability are critical in the development of high-performance Al-Mg alloys.Here,we attempt to tailor Al_(3)(Sc,Zr)precipitates and thus microstructure characteristics to manipulate mechanical properties and microstructural stability of Al-7Mg alloys fabricated by hot extrusion com-bined with two-pass hard-plate rolling via changing Sc/Zr ratio.Increasing Sc/Zr ratio leads to improved strength without any loss of ductility.A strength-ductility synergy,i.e.yield strength of∼548 MPa and ultimate tensile strength of∼605 MPa with an impressive ductility of∼10%elongation was achieved in the Al-7Mg-0.3Sc-0.1Zr alloy.The good strength-ductility synergy is ascribed to the multi-scale het-erogeneous microstructure promoted by the high Sc/Zr ratio,i.e.a bimodal grain structure,profuse low angle grain boundaries,dispersed nano-sized Al_(3)(Sc,Zr)precipitates coexisting with intragranular Mg-Zr co-clusters segregated at dislocations.Upon thermal exposure,the Al-7Mg-0.3Sc-0.1Zr alloy maintained higher hardness at below 250°C,whereas Al-7Mg-0.2Sc-0.2Zr and Al-7Mg-0.1Sc-0.3Zr alloys exhibited higher hardness in moderate-and high-temperature range of 250-350℃and≥400℃,respectively.Atom-probe tomography analysis illustrates that slow-diffusing Zr atoms enhance Al_(3)(Sc,Zr)coarsening resistance through forming a higher-content Zr-enriched protective shell around a Sc-enriched core in Al-7Mg-0.1Sc-0.3Zr.Meanwhile,the high Zr content promotes concurrent Al_(3)(Sc,Zr)precipitation during thermal exposure at high temperatures.The improved microstructural thermal stability in Al-7Mg-0.1Sc-0.3Zr alloy is further discussed in terms of the recrystallization resistance and grain growth behavior.The present study reveals the feasibility for designing high-strength and thermally stable hetero-structured Al-Mg-Sc-Zr alloys via tailoring Sc/Zr ratios for different application temperature ranges.展开更多
Three ethylene-vinyl alcohol copolymers were studied by means of the substituent chemical shift (SCS) method. The SCS parameters of hydroxy (-OH) in two different solvents were obtained: in deuterium oxide/phenol (20/...Three ethylene-vinyl alcohol copolymers were studied by means of the substituent chemical shift (SCS) method. The SCS parameters of hydroxy (-OH) in two different solvents were obtained: in deuterium oxide/phenol (20/80 W/W ) the parameters are S_1 = 42.77±0.08ppm, S_2 = 7.15±0.06 ppm, S_3 (s)= -4.08±0.02ppm, S_3 (t) =-3.09±0.20ppm,S_4 = 0.48±0.03ppm, S_5 = 0.26±0.05ppm. In o-dichloro-benzen-d_4 S_1(s)=44.79±0.61ppm, S_2=7.40±0.00ppm, S_3(s)=-4.51±0.17ppm, S_3(t)=-3.13 ±0.00 ppm, S_4 =0.63±0.04ppm, S_5=0.36±0.00ppm.Simultaneously the ^(13)CNMR spectra of EVA copolymers were assigned by using the SCS parameters obtained.展开更多
Spin-unrestricted localized INDO method was used to calculate the electronic structure of rare earth cluster Sc(Sc_6Cl_(12)Co).Based on the analysis of the composition of the molecular orbitals and bond orders,it was ...Spin-unrestricted localized INDO method was used to calculate the electronic structure of rare earth cluster Sc(Sc_6Cl_(12)Co).Based on the analysis of the composition of the molecular orbitals and bond orders,it was pointed out that the interstitial transition metal atom Co in the octahedral Sc skeleton forms strong covalent bond with six Sc atoms and the bonding of Sc- Cl is mainly ionic in character.There are nine valence molecular orbitals in the cluster.展开更多
The crystal of the title compound Sr6Gd0.61Sc1.39(BO3)6 (Mr = 1037.00) was grown by Czochralski method. It crystallizes in trigonal, space group 3Rwith a = 12.415(2), c = 9.274(2) ? Z = 3, V = 1238.0(4) 3, Dc = 4.173 ...The crystal of the title compound Sr6Gd0.61Sc1.39(BO3)6 (Mr = 1037.00) was grown by Czochralski method. It crystallizes in trigonal, space group 3Rwith a = 12.415(2), c = 9.274(2) ? Z = 3, V = 1238.0(4) 3, Dc = 4.173 g/cm3, l(MoKa) = 0.71073 ? m = 22.278 mm-1, F(000) = 1411, S = 1.213, the final R = 0.0577 and wR = 0.1414 for 401 observed reflections with I>2s(I). In the structure Gd(1)O6 (Gd(1) = Gd0.46 + Sc0.54) and Gd(2)O6 (Gd(2)= Gd0.15 + Sc0.85) are alternately stacked between the planar triangular BO3 groups to form chains extending along the trigonal axis. These chains are connected through the 9-coordinate Sr atoms.展开更多
[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15c...[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .展开更多
基金supported by the Natural Science Foundation of China(Nos.51922048,52234009 and 51871108)Partial financial support from the Changjiang Scholars Program(No.T2017035)+1 种基金the Science and Technology Development Program of Jilin Province(No.20200401030GX)the Natural Science Foundation of Jiangsu Province(No.BK 20220629)was greatly acknowledged.
文摘Microstructure and its thermal stability are critical in the development of high-performance Al-Mg alloys.Here,we attempt to tailor Al_(3)(Sc,Zr)precipitates and thus microstructure characteristics to manipulate mechanical properties and microstructural stability of Al-7Mg alloys fabricated by hot extrusion com-bined with two-pass hard-plate rolling via changing Sc/Zr ratio.Increasing Sc/Zr ratio leads to improved strength without any loss of ductility.A strength-ductility synergy,i.e.yield strength of∼548 MPa and ultimate tensile strength of∼605 MPa with an impressive ductility of∼10%elongation was achieved in the Al-7Mg-0.3Sc-0.1Zr alloy.The good strength-ductility synergy is ascribed to the multi-scale het-erogeneous microstructure promoted by the high Sc/Zr ratio,i.e.a bimodal grain structure,profuse low angle grain boundaries,dispersed nano-sized Al_(3)(Sc,Zr)precipitates coexisting with intragranular Mg-Zr co-clusters segregated at dislocations.Upon thermal exposure,the Al-7Mg-0.3Sc-0.1Zr alloy maintained higher hardness at below 250°C,whereas Al-7Mg-0.2Sc-0.2Zr and Al-7Mg-0.1Sc-0.3Zr alloys exhibited higher hardness in moderate-and high-temperature range of 250-350℃and≥400℃,respectively.Atom-probe tomography analysis illustrates that slow-diffusing Zr atoms enhance Al_(3)(Sc,Zr)coarsening resistance through forming a higher-content Zr-enriched protective shell around a Sc-enriched core in Al-7Mg-0.1Sc-0.3Zr.Meanwhile,the high Zr content promotes concurrent Al_(3)(Sc,Zr)precipitation during thermal exposure at high temperatures.The improved microstructural thermal stability in Al-7Mg-0.1Sc-0.3Zr alloy is further discussed in terms of the recrystallization resistance and grain growth behavior.The present study reveals the feasibility for designing high-strength and thermally stable hetero-structured Al-Mg-Sc-Zr alloys via tailoring Sc/Zr ratios for different application temperature ranges.
文摘Three ethylene-vinyl alcohol copolymers were studied by means of the substituent chemical shift (SCS) method. The SCS parameters of hydroxy (-OH) in two different solvents were obtained: in deuterium oxide/phenol (20/80 W/W ) the parameters are S_1 = 42.77±0.08ppm, S_2 = 7.15±0.06 ppm, S_3 (s)= -4.08±0.02ppm, S_3 (t) =-3.09±0.20ppm,S_4 = 0.48±0.03ppm, S_5 = 0.26±0.05ppm. In o-dichloro-benzen-d_4 S_1(s)=44.79±0.61ppm, S_2=7.40±0.00ppm, S_3(s)=-4.51±0.17ppm, S_3(t)=-3.13 ±0.00 ppm, S_4 =0.63±0.04ppm, S_5=0.36±0.00ppm.Simultaneously the ^(13)CNMR spectra of EVA copolymers were assigned by using the SCS parameters obtained.
文摘Spin-unrestricted localized INDO method was used to calculate the electronic structure of rare earth cluster Sc(Sc_6Cl_(12)Co).Based on the analysis of the composition of the molecular orbitals and bond orders,it was pointed out that the interstitial transition metal atom Co in the octahedral Sc skeleton forms strong covalent bond with six Sc atoms and the bonding of Sc- Cl is mainly ionic in character.There are nine valence molecular orbitals in the cluster.
基金Supported by the National Natural Science Foundation of China (50272066) and the Key Project of Science and Technology of Fujian Province (2001H107)
文摘The crystal of the title compound Sr6Gd0.61Sc1.39(BO3)6 (Mr = 1037.00) was grown by Czochralski method. It crystallizes in trigonal, space group 3Rwith a = 12.415(2), c = 9.274(2) ? Z = 3, V = 1238.0(4) 3, Dc = 4.173 g/cm3, l(MoKa) = 0.71073 ? m = 22.278 mm-1, F(000) = 1411, S = 1.213, the final R = 0.0577 and wR = 0.1414 for 401 observed reflections with I>2s(I). In the structure Gd(1)O6 (Gd(1) = Gd0.46 + Sc0.54) and Gd(2)O6 (Gd(2)= Gd0.15 + Sc0.85) are alternately stacked between the planar triangular BO3 groups to form chains extending along the trigonal axis. These chains are connected through the 9-coordinate Sr atoms.
基金Project supported by the National Natural Science Foundation of China
文摘[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .
